Fix TreeScopeAdopter in case of nested shadow trees moving across documents

https://crrev.com/517033 still misses a case where shadow trees are nested, which was the cause of
DCHECK [1] failure of the test [2]. This CL fixes that.

[1] https://cs.chromium.org/chromium/src/third_party/blink/renderer/core/dom/node.cc?q=MayContainLe&sq=package:chromium&l=773
[2] virtual/incremental-shadow-dom/media/controls/overlay-play-button-document-move.html.

Bug: 776656,783055
Change-Id: I22005d1518768c1750be33a818d25230efa26b76
Reviewed-on: https://chromium-review.googlesource.com/1056927
Commit-Queue: Hayato Ito <hayato@chromium.org>
Reviewed-by: Takayoshi Kochi <kochi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#558243}

third_party/WebKit/LayoutTests/TestExpectations

@@ -1724,7 +1724,6 @@ crbug.com/591099 virtual/layout_ng_experimental/external/wpt/css/css-flexbox/ord
 crbug.com/776656 virtual/incremental-shadow-dom/external/wpt/shadow-dom/untriaged/styles/test-003.html [ Failure ]
 
 crbug.com/776656 virtual/incremental-shadow-dom/media/controls/controls-cast-do-not-fade-out.html [ Pass Timeout ]
-crbug.com/776656 virtual/incremental-shadow-dom/media/controls/overlay-play-button-document-move.html [ Failure Crash ]
 
 # These tests are also failing without the flag
 crbug.com/832447 virtual/incremental-shadow-dom/media/controls/controls-page-zoom-in.html [ Failure Pass ]

third_party/blink/renderer/core/dom/tree_scope_adopter.cc

@@ -82,20 +82,25 @@ void TreeScopeAdopter::MoveTreeToNewScope(Node& root) const {
 
     if (ShadowRoot* shadow = element.GetShadowRoot()) {
       shadow->SetParentTreeScope(NewScope());
-      if (will_move_to_new_document) {
-        if (shadow->GetType() == ShadowRootType::V0) {
-          new_document.SetShadowCascadeOrder(
-              ShadowCascadeOrder::kShadowCascadeV0);
-        } else if (shadow->IsV1() && !shadow->IsUserAgent()) {
-          new_document.SetShadowCascadeOrder(
-              ShadowCascadeOrder::kShadowCascadeV1);
-        }
-        MoveTreeToNewDocument(*shadow, old_document, new_document);
-      }
+      if (will_move_to_new_document)
+        MoveShadowTreeToNewDocument(*shadow, old_document, new_document);
     }
   }
 }
 
+void TreeScopeAdopter::MoveShadowTreeToNewDocument(
+    ShadowRoot& shadow_root,
+    Document& old_document,
+    Document& new_document) const {
+  DCHECK_NE(old_document, new_document);
+  if (shadow_root.GetType() == ShadowRootType::V0) {
+    new_document.SetShadowCascadeOrder(ShadowCascadeOrder::kShadowCascadeV0);
+  } else if (shadow_root.IsV1() && !shadow_root.IsUserAgent()) {
+    new_document.SetShadowCascadeOrder(ShadowCascadeOrder::kShadowCascadeV1);
+  }
+  MoveTreeToNewDocument(shadow_root, old_document, new_document);
+}
+
 void TreeScopeAdopter::MoveTreeToNewDocument(Node& root,
                                              Document& old_document,
                                              Document& new_document) const {
@@ -113,8 +118,8 @@ void TreeScopeAdopter::MoveTreeToNewDocument(Node& root,
         MoveTreeToNewDocument(*attr, old_document, new_document);
     }
 
-    if (ShadowRoot* shadow = element.GetShadowRoot())
-      MoveTreeToNewDocument(*shadow, old_document, new_document);
+    if (ShadowRoot* shadow_root = element.GetShadowRoot())
+      MoveShadowTreeToNewDocument(*shadow_root, old_document, new_document);
   }
 }
 

third_party/blink/renderer/core/dom/tree_scope_adopter.h

@@ -54,6 +54,9 @@ class CORE_EXPORT TreeScopeAdopter {
   void MoveTreeToNewDocument(Node&,
                              Document& old_document,
                              Document& new_document) const;
+  void MoveShadowTreeToNewDocument(ShadowRoot&,
+                                   Document& old_document,
+                                   Document& new_document) const;
   void MoveNodeToNewDocument(Node&,
                              Document& old_document,
                              Document& new_document) const;

third_party/blink/renderer/core/dom/tree_scope_adopter_test.cc

@@ -11,6 +11,8 @@
 
 namespace blink {
 
+// TODO(hayato): It's hard to see what's happening in these tests.
+// It would be better to refactor these tests.
 TEST(TreeScopeAdopterTest, SimpleMove) {
   Document* doc1 = Document::CreateForTest();
   Document* doc2 = Document::CreateForTest();
@@ -111,4 +113,35 @@ TEST(TreeScopeAdopterTest, AdoptV0ShadowRootToV1Document) {
   EXPECT_TRUE(doc2->MayContainV0Shadow());
 }
 
+TEST(TreeScopeAdopterTest, AdoptV0InV1ToNewDocument) {
+  Document* old_doc = Document::CreateForTest();
+  Element* html = old_doc->CreateRawElement(HTMLNames::htmlTag);
+  old_doc->AppendChild(html);
+  Element* host1 = old_doc->CreateRawElement(HTMLNames::divTag);
+  html->AppendChild(host1);
+  ShadowRoot& shadow_root_v1 =
+      host1->AttachShadowRootInternal(ShadowRootType::kOpen);
+  Element* host2 = old_doc->CreateRawElement(HTMLNames::divTag);
+  shadow_root_v1.AppendChild(host2);
+  host2->CreateShadowRootInternal();
+
+  // old_doc
+  // └── html
+  //     └── host1
+  //         └──/shadow-root-v1
+  //             └── host2
+  //                 └──/shadow-root-v0
+  EXPECT_TRUE(old_doc->MayContainV0Shadow());
+
+  Document* new_doc = Document::CreateForTest();
+  EXPECT_FALSE(new_doc->MayContainV0Shadow());
+
+  TreeScopeAdopter adopter(*host1, *new_doc);
+  ASSERT_TRUE(adopter.NeedsScopeChange());
+  adopter.Execute();
+
+  EXPECT_TRUE(old_doc->MayContainV0Shadow());
+  EXPECT_TRUE(new_doc->MayContainV0Shadow());
+}
+
 }  // namespace blink